This invention relates to a manually operated injection apparatus that permits medically untrained individuals to easily self-administer liquid medicaments, and more particularly relates to an injection apparatus that is capable of rapid, easily mastered multiple refills of medicament which may be required for treatment of medical emergencies. For example, this device can be used with adrenalin for several life-threatening medical emergencies such as: bee sting reactions, immediate allergic-like reactions to ingestants such as drugs, foods, food additives (metabisulfite, monosodium glutamate, yellow tartrazine coloring dyes), acute hives with associated shock-like symptoms, acute bronchial asthma, etc. More than a single dose of adrenalin can be required to treat and reverse these life-threatening situations. These adrenalin injection devices can be particularly life-saving for individuals when immediate medical attention is not available.
There are several problems inherent in existing self-administration injection designs. These include (1) complicated designs which are difficult to understand and use. In addition, certain designs exhibit needle visibility which can cause undue fear reactions in individuals who must self-administer life-saving drugs. (2) expensive retail costs reducing consumer availability. This problem is reflective of design and manufacturing complexity of the injection device (3) according to its instructions, one device is incapabile of operating when the injection device is cold, which will cause time delays in treating medical emergencies. (4) lack of or difficult refilling capabilities needed for treatment of medical emergencies that do not respond to a single dose of medicament.
The following patent references were selected from a search through the U.S. Patent and Trademark Office as the closest patented art in the field: Leiter, U.S. Pat. No. 159,192; Morton, U.S. Pat. No. 1,767,304; Lockhart, U.S. Pat. No. 2,408,323; Maynes, U.S. Pat. No. 2,472,116; Smith, U.S. Pat. No. 2,475,061; Tydings, U.S. Pat. No. 2,489,600; Harnisch, U.S. Pat. No. 2,671,448; Huber, U.S. Pat. No. 2,688,965; Jensen, U.S. Pat. No. 2,704,073; Uytenbogaart, U.S. Pat. No. 2,752,918; Rockwell, U.S. Pat. No. 2,856,924; Wilburn, U.S. Pat. No. 2,860,635; Craig, U.S. Pat. No. 2,925,083; Roehr, U.S. Pat. No. 3,008,570, Hershberg, U.S. Pat. No. 3,572,336; Sarnoff, U.S. Pat. No. 3,882,863; Leeson, U.S. Pat. No. 3,890,971; Rimbaud, U.S. Pat. No. 3,930,499; Norgren, U.S. Pat. No. 3,943,927.
The following patent designs and commercially available devices exhibit some of the aforementioned limitations.
U.S. Pat. No. 2,475,061 issued to A. E. Smith (1) is a complicated manual operated design which requires first unthreading and removing a skirt and plunger from housing sleeve, then manually assisting ampule through an introduction slot, and finally replacing and rethreading skirt with plunger onto housing sleeve and (2) by patent description requires that the needle be visible prior to the injection of medicament into the skin.
U.S. Pat. No. 2,489,600 issued to Tydings and Tash is also a complicated manually operated design which requires first removal of plunger and skirt and insertion of ampule and needle combination into housing. The needle must be pushed through ampule plug and by patent description the needle becomes visible before it is injected into the skin. Thereafter there is a complicated method to refill since it is necessary to inject medicament into the existing ampule in housing with an auxiliary syringe and needle device.
One commercially available kit with no listed patent number (ANA Kit), has needle visibility and a complicated three stage plunger design that can be confusing. The first push of the plunger which is designed to remove excess air and liquid can be confused with the second stage push which actually administers a full dose of medicament. Additionally, the second dose of medicament can only be used in the same time frame, as the needle has been used once and would thus be contaminated for use at a later time period.
A manually-activated injection device disclosed in U.S. Pat. No. 3,943,927 issued to Norgren: (1) uses cross arms that move outwardly from center of housing. The net result is a design requirement for a larger diameter housing, making it potentially awkward for manual handling, and (2) does not exhibit multi-dose capabilities because once the medicationis pushed through the needle that punctures relief area, there is no provision to permit delivery of a second dose of medicament or to refill the housing with a second refill cartridge.
Another commercially available design disclosed in U.S. Pat. No. 3,882,863 issued to Sarnoff and Catkins is: (1) a complicated coiled-spring release mechanism that is expensive to produce, (2) potentially dangerous to the user if the powerful coiled-spring is released through a defective plastic housing, (3) not be operated if it is refrigerated or stored in cold conditions, which may cause serious time delays in delivery of an emergency medicament since the device should only be used after it equilibrates to a temperature between 59.degree.-86.degree. F., (4) not capable of multidose administration since once the coiled-spring mechanism has been actuated, there is no provision for delivery of a second dose of medicament.